Liquid fuel pumping apparatus for supplying fuel to multi-cylinder internal combustion engines



3,410,216 G APPARATUS FOR SUPPLYING FUEL -CYLINDER INTERNAL COMBUSTION ENGINES Nov. 12 1968 K. A. w. KEMP LIQUID FUEL PUMPIN MULTI Filed March 24. 1967 3 Sheets-Sheet l United States Patent m 3,410,216 LIQUID FUEL PUMPING APPARATUS FOR SUP- PLYING FUEL T0 MULTI-CYLINDER INTERNAL COMBUSTION ENGINES Kenneth Albert Walters Kemp, Ealing, London, England, assignor to C.A.V., Limited, London, England, a British company Filed Mar. 24, 1967, Ser. No. 625,790 Claims priority, application Great Britain, Mar. 31, 1966, 14,222/ 66 11 Claims. (Cl. 103-2) ABSTRACT OF THE DISCLOSURE Pumping apparatus of the rotary distributor type for supplying fuel to an internal combustion engine, the distributor being provided with two transverse bores in which are located pairs of pumping plungers respectively, a pair of cams arranged to move the plungers inwardly as the distributor is rotated, the distributor having two sets of passages through which fuel flows to two sets of delivery ports, during the injection stroke and a common feed pump for supplying fuel to the transverse bores, there also being provided a common metering valve for controlling the quantity of fuel supplied to the bores.

This invention relates to liquid fuel pumping apparatus for supplying fuel to multi-cylinder internal combustion engines and has for its object to provide such an apparatus in a simple and convenient form.

Apparatus in accordance with the invention comprises in combination, a body part, a rotary cylindrical distributor mounted within the body part, the distributor being adapted to be driven in timed relationship to the engine with which the apparatus is associated, first and second bores defined within the distributor, first and second plungers reciprocably mounted within the bores respectively, a pair of cams for imparting inward movement to the first and second plungers respectively as the distributor rotates, a pair of longitudinal passages formed by the distributor and in communication with the first and second bores respectively, a pair of outwardly extending inlet passages formed in the distributor and in communication with the longitudinal passages respectively, inlet ports formed in the body part for registration with the inlet passages as the distributor rotates during the time when the respective plungers are allowed to move outwardly by the cams, a pair of delivery passages formed by the distributor and in communication with the longitudinal passages respectively, said delivery passages being axially offset relative to each other, first and second outlet ports formed in the body part for registration with the delivery passages respectively as the distributor rotates during the time when the respective plungers are being moved inwardly by the cams and means for controlling the flow of fuel through said inlet ports from a source of fuel under pressure.

In the accompanying drawings:

FIGURE 1 is a sectional side elevation of one example of an apparatus in accordance with the invention,

FIGURE 2 is a section of part of the apparatus taken on the line 2-2 of FIGURE 1 looking in the direction of the arrow,

FIGURE 3 is a section on the line 3-3 of FIGURE 1 looking in the direction of the arrow, and

FIGURE 4 is a section on the line 44 of FIGURE 2.

Before describing the arrangement and operation of the pumping apparatus it should be mentioned that the passages shown in dotted outline in the rotary part of 3,410,216 Patented Nov. 12, 1968 the apparatus in FIGURE 1 are not in their correct positions they are shown in the positions in which they are shown for ease of illustration. The positions of the passages is correct however in FIGURES 2, 3 and 4.

The liquid fuel pumping apparatus now to be described in conjunction with the accompanying drawings is, for supplying fuel to an eight cylinder engine. The apparatus includes a body part 10 in which is mounted a rotary cylindrical distributing member 11 which is arranged to be rotated in timed relationship to the engine with which the apparatus is associated by means of an input shaft 12 journalled within the body part. At the end of the body part remote from the input shaft there is mounted a feed pump 13 having a rotary part 14 which is connected to the adjacent end of the distributor member. The feed pump has an outlet 15 in the body part and which com municates with an annular feed channel 16 also defined within the body part.

The feed channel is in communication with an outwardly extending bore in which is mounted an angularly adjustable throttle member 17 the setting of which controls the rate of flow of fuel from the feed channel to a further annular feed channel 18 formed in the body part.

Formed in the end portion of the distributor member remote from the feed pump are a pair of transversely disposed bores 19a and 19b the axes of which are substantially parallel to each other. Within each bore is mounted a pair of pumping plungers 20 which are arranged to be moved inwardly by a pair of cams 21a and 21!) mounted within the body part, there being provided intermediate the ends of the plunger and cams, rollers 22 which are supported by shoes slidable in slots in the distributor. The cams 21a and 21b each comprise an annular ring on the internal periphery of which are formed two pairs of diametrically disposed cam lobes. The two pairs of lobes are at to each other. In known manner the angular setting of the cams within th body part is adjustable and for this purpose the cam 21b is provided with an outwardly extending arm 23 which may be connected to a fluid operable piston (not shown). The cam 21a is coupled to the cam 21b by axially extending pegs 24 so that the two cams will move angularly as one and the relative setting of th cam rings is such that one pair of lobes on one cam is disposed at 45 relative to the pairs of lobes on the other cam.

Within the distributor is formed a pair of longitudinal passages 25a and 25b and these are in communication with the bores 19a and 1% respectively.

The passage 25b is axially disposed within the distributing member. Extending outwardly from the passages 25a and 2512 are a pair of delivery passages 26a and 26b respectively and these passages are axially offset relative to each other. Formed in the body part for cooperation with the delivery passages respectively are two series of outlet ports 27a and 27b each series having four ports. In each series of outlet ports the individual ports are equiangularly spaced about the body part and are adapted for connection at their outer ends with the injection nozzles respectively of the associated engine. Moreover, the two series of delivery ports are disposed so that a port in one series is disposed at 45 to a port of the other series.

The longitudinal passage 25a and 25b are also in communication with a pair of outwardly extending and axially offset inlet passages 28a and 28b respectively and these are arranged to register as the distributor rotates, with two series of inlet ports 29a and 29b respectively, each series having four ports. At their outer ends the two series of inlet ports are in communication with the annular feed channel 18.

The apparatus can be considered as two four cylinder pumps sharing a common distributing member 11, a common throttling member 17 and a common feed pump and in view of this the operation of only one of the pumps will be described. As the distributor rotates inward movement will be imparted to one pair of plungers 20 and fuel will be displaced from the pumping chamber defined therebetween, along one of the longitudinal passages in the distributing member to the associated delivery passage and through one of the delivery ports to the appropriate engine cylinder. As the distributor further rotates the delivery passage will be moved out of register with the delivery port and the appropriate inlet port will be brought into registration with the inlet passage. When this occurs fuel flows from the feed channel into the longitudinal passage and causes the pumping plungers 26 to be moved outwardly. The rate at which fuel flows into the longitudinal passage is controlled by the setting of the throttling member 17 and this may be controlled either manually or by means of a governor which is responsive to the speed at which the engine is driven. As the distributor further rotates the inlet passage will move out of register with an inlet port and the delivery passage will be brought into register with the next delivery port. Thereafter the cycle will be repeated as described. By virtue of the disposition of the pumps Whilst one pump is delivering fuel the other pump is being filled.

The relative angular disposition of the two pumps depends upon the type of engine to which fuel is being supplied. In the example a pump for supplying fuel to an eight cylinder engine has been described and in this case fuel is supplied by one or the other of the pumps at 45 intervals throughout the angular movement of the distributor.

In another example the engine to which fuel is to be supplied is a 6 cylinder 90 V-engine which must receive fuel at alternate intervals of 45 and 75 of distributor rotation. In this case each pump would supply fuel at intervals of 120 so that there would be three ports in each series and three pairs of equi-angularly spaced cam lobes on each cam. Moreover, the cam rings would be set at relative to each other.

In some cases the cam lobes are shaped to provide a predetermined amount of relief of the pressure in the outlet ports at the end of the inward movement of the plungers. This presents no difiiculty in the case of pumps which supply fuel to four cylinder engines and therefore no difficulty arises with the first examples. In the case of the last example certain difiiculties arise and these are explained in the specification of our British Patent No. 1,046,951. Also described and claimed in this specification is a pumping apparatus for supplying fuel to a three cylinder engine in which the difiiculties are overcome. Two such pumps as described in this specification can be used in the present apparatus. As an alternative to the arrangement described in this specification the recuperation chamber may be omitted and the fuel which is expelled from the bores containing the plungers may be allowed to flow to a source of low pressure fuel such for instance, as the outlet of the feed pump.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A liquid fuel pumping apparatus for supplying fuel to a multi-cylinder internal combustion engine and comprising in combination, a body part, a rotary cylindrical distributor mounted within the body part, the distributor being adapted to be driven in timed relationship to the engine with which the apparatus is associated, first and second bores defined within the distributor, first and second plungers reciprocably mounted within the bores respectively, a pair of cams for imparting inward movement to the first and second plungers respectively as the distributor rotates, a pair of longitudinal passages formed by the distributor and in communication with the first and second bores respectively, a pair of outwardly extending inlet passages formed in the distributor and in communication with the longitudinal passages respectively inlet ports formed in the body part for registration with the inlet assages as the distributor rotates during the time when the respective plungers are allowed to move outwardly by the earns, a pair of delivery passages formed by the distributor and in communication with the longitudinal passages respectively, said delivery passages being axially offset relative to each other, first and second outlet ports formed in the body part for registration with the delivery passages respectively as the distributor rotates during the time when the respective plungers are being moved inwardly by the cams and means for controlling the fiow of fuel through said inlet ports from a source of fuel under pressure.

2. An apparatus as claimed in claim 1 in which said means comprises a single throttle member.

3. An apparatus as claimed in claim 1 in which said source comprises a feed pump mounted in the body part and having a rotary part driven by the distributor.

4. An apparatus as claimed in claim 3 in which said cams are formed on the internal peripheries of a pair of cam rings respectively.

5. An apparatus as claimed in claim 4 in which the cam rings are coupled together and are mounted within the body part for angular movement about the axis of rotation of the distributor.

6. An apparatus as claimed in claim 4 in which each bore accommodates a pair of plungers and each cam ring is provided with a pair of diametrically disposed cams for actuating said plungers.

7. An apparatus as claimed in claim 6 in which further pairs of cams are formed on said cam rings the pairs of cam on each ring being equi-angularly disposed relative to each other, there being provided additional first and second inlet ports and first and second outlet ports for cooperation with the inlet passages and the first.and second outlet passages respectively.

8. An apparatus as claimed in claim 7 in which each cam ring is provided with three pairs of cam lobes there being the same number of first and second inlet ports and first and second outlet ports.

9. An apparatus as claimed in claim 8 in which the cams are shaped to permit relief of the pressure in the outlet ports at the end of the inward movement of the plungers, there being provided means to receive and return the small quantity of fuel displaced by the plungers as they pass the next pair of earns.

10. An apparatus as claimed in claim 9 in which said means comprises a recuperation chamber into which the fuel is displaced.

11. An apparatus as claimed in claim 9 in which said means comprises a source of low pressure fuel such as the outlet of the feed pump.

References Cited UNITED STATES PATENTS 2,946,292 7/ 1960 Chmielecki 1032 X 3,177,860 4/1965 Glikin. 3,263,614 8/1966 Kemp. 3,058,425 10/1962 Evans.

FOREIGN PATENTS 167,404 5/1965 U.S.S.R.

FRED C. MATTERN, JR., Primary Examiner.

W. J. KRAUSS, Assistant Examiner. 

